The invention is based on a fuel injection pump.
In slide-controlled fuel injection pumps, the axial position of the control slide usually determines the start of injection or the end of injection. However, there are also such pumps in which the injection quantity is controlled by means of the axial position of the control slide. In any case, an inexact axial position of the control slide has disadvantageous consequences for the quality of injection, which has immediate consequences for the combustion, with the result that the engine runs untrue because of the incorrectly timed injection or runs too quickly or two slowly because of the inexact metering quantity.
In a known fuel injection pump of this type (EP-A 0 181 402), the adjusting bolt engages in the cross groove of the control slide with a spherical head so that there is a punctiform contact between the head and the groove surfaces, which, with the long operating life and high vibration load of these actuating elements, leads to a premature wear and, accordingly, to an undesired play between the head and the groove surfaces with corresponding errors in the fuel control. The installation position of the adjusting bolt is fixed during adjustment, since, because of the eccentric arrangement of the head, the adjustment of the stroke position of the control slide is effected by means of turning the adjusting bolt, with subsequent checking. The play which occurs because of wear, however, works against this adjustment with the results mentioned above.
In another known fuel injection pump of this type (DE-A35 22 414), the adjusting bolt is arranged at a clamping ring so as to be fixed with respect to rotation relative to it; the clamping ring serves as a fastening part and grips the round rotating shaft in a clamp-like manner. The required adjustment can be carried out in a relatively simple manner by means of rotating the clamp on the rotating shaft, but there are also other disadvantages besides the one already mentioned, in that the transmission of force between the adjusting bolt and the respective surfaces of the cross groove is effective in a punctiform manner, since the adjusting bolt is constructed as a rotating part. Accordingly, since the contact is only punctiform, a correspondingly quick and severe wear also occurs in this case on the adjusting bolt as well as on the assigned groove surfaces.